In the food, beverage and dairy market there exists a wide array of shelf stable packaged liquid and semi-liquid foods. These range from canned soups, to highly acidified soda and sport drinks.
Until 30 years ago the only options available for production of a shelf stable food with low acidity was thermal sterilization of both the packing and the food in a unitized manner. This was done either through pressure cooking, processing of sealed containers, or by filling thermally resistant packaging with a hot liquid food (the heat of the liquid food thereby sterilizing the packaging).
The introduction of aseptic packaging called for thermal sterilization of a liquid food stuff and separate chemical sterilization of the food packaging. This allowed for shorter thermal treatment of the food and the processing of foods that would have normally not been suitable for shelf stable food processing.
A chemical sterilant used in aseptic packaging is peracid. Peracid exists in equilibrium with its corresponding carboxylic acid and hydrogen peroxide. The equilibrium shifts to the reactant side or the product side of the chemical equilibrium equation based on the concentration of reactants or products present in a given solution.
Normally a peracid is provided to an end-user as an equilibrium concentrate and the end-user dilutes the concentrate to the level that is required for microbial treatment of their surface of interest. Over time, the peracid inside a sump in aseptic packaging operation slowly degrades or equilibrates back to the carboxylic acid and hydrogen peroxide. As a result, the sump accumulates higher levels of hydrogen peroxide and carboxylic acid. Filler manufacturers and customers have specifications set for maximum levels of hydrogen peroxide or carboxylic acid in the sump. When the sump approaches this limit it can be shut down, drained and refilled with fresh solution. Other filler manufactures will set the system up so that it has a certain bleed off rate. Adjusting the bleed off rate will modify the accumulation rate of peroxide and carboxylic acid in the sump so that the line can be run for an extended length of time. Both of these procedures increase the amount of water, energy, and chemistry required to operate an aseptic filler. It is against this background that the present invention has been made.